Electric furnace.



C. G. MINER.

ELECTRIC FURNACE.

APPLICATION men rca. n. 19n- 1,232,362. Patented Jilly 3, 1917.

Fig.1

E INVENTOR WITNESSES Iii/W myflw ATTORNEY CLAUDE G. MINER, OF BERKELEY,CALIFORNIA.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented July 3, 1917.

Application filed February 17, 1917. Serial No. 149,248.

To all whom it may concern:

Be it known that I, CLAUDE G. MINER, a citizen of the United States,residing at Berkeley, in the county of Alameda and State of California,have invented new and useful Improvements in ElectricFurnaces, of whichthe following is a specification.

This invention relates to improvements in electric furnaces.

The rimary object of this invention is to provide a t pe of an electricfurnace especially suita le for laboratory and sclen; tific work on a.small scale.

Another object is to provide a furnace which is adapted to the use ofinexperienced operators, and more especially, capable of beingreadilyaltered from the arc to the resistor type by such operators.

A third object is to combine in such a furnace means by' which .rapidand intense heating is secured, together with economy of o ration.

dish these and other objects 1n view, which will appear upon perusal ofthemcompanying description and claims, and an examination of thedrawings herewith, I have embodied my invention in the form shown anddescribed below.

In the drawings, Fi re 1 is a sectional side elevation of the mace.

Fig. 2 is a sectional plan view taken at a point midway of the reactionchamber of the furnace.

Fig. 3 illustrates a cover block provided for the crucible of thefurnace when the resistant principle is utilized. bl Fig is a sectionalview of the cover Referring now to the drawings in detail, 1 designatesstandards servi-n as a support for the outer wall 2 of the in may beconstructed of firebrick or other suitable refractory material. Insidewall 2, but separated therefrom by cavities 3, filled with heatinsulating material, is a mass of refractory material 4 wherein thereaction chamber 5 is situated, said reaction chamber bein in formsimilar to two opposed paraboloi havin the ma'or axis thereof exe upperportion of tending vertlcally.

rnace which reaction chamber 5 is provided with an observation tubeextending through the outer portions of the furnace, and similar tubes,14 and 15, for the escape or admission of gases. Horizontally placedmidway between the top and bottom of said reaction chamber is a support6 for the crucible 7.

The purpose of giving to chamber 5 a parab oloid form is to securegreater concentration of heat upon the crucible 7, which is preferablyplaced in the principal foci of the paraboloids.

Another advantage of this shape of chamber arises from the fact that thecubic capacity is thereby reduced, resulting in econ omy of electricalconsumption.

Economical operation is furthermore assisted by the cavity 3 filled withheat insulating material; which is preferably comosed of infusorialearth, this material bemg an excellent non-conductor of heat.

Downwardly extending throu h walls 2 and 4 into the combustion cham er 5is an electrode 8, of. carbon or other suitable material, said electrodebein provided with a support and means of a justment 9 secured to theouter wallof the furnace, and being further provided with suitable meansof electric connection. A second electrode 10 which may or may not besomewhat larger than electrode 8 and provided with a similar means ofsuppprt and adjustment 11,

extends upwardly through'walls 2 and 4 into thereaction chamber 5, andis similarlyprovided with means of electric connection. A thirdelectrode 12 extends laterally through walls 2 and 4, terminating at apoint slightly within chamber 5 and establishin connection with thecrucible support 6. This crucible support when for use in connectionwith the series are rinciple is made of refractory but non-con uctinmaterial, the crucible in this case-being 0 carbon or other refractoryconducting material such as commonly is used in the art;

When operating the furnace upon 'the arc principle, the electrode 10 israised by means of an adjustment 11 until it establishes connection withcrucible 7, electrode 8 being then lowered until it contacts with the uper portion of crucible 7, and quickly withdrawn, thereby creating anarc. If desired, electrode may now be drawn out of contact with crucible7, producing a second arc, resulting in extremely intense and rapidheating of the contents of the crucible 7.

This method of operation utilizes in series 'connection the two arcs,but as sufiicient .fractory conducting material such as commonly used inthe art, forinstance, carbon,

' being substituted. Electrodes 8 and 10 are then connected to one leadfrom the source of current sup ly, terminal 12 being connected to the oter lead.

As it is often desirable to utilize the resistance principle ofoperation in such a furnace means of readily altering the furnace toeli'ect this are rovided, these means consisting of a con uctingrefractory support dsimllar to that used when operating with arcs inparallel, but used in this connection i at adjustment 11, and the lowerwith the non-conducting crucible 7 of refractory material. A suitablecover-block 13 of refractory conducting material is pro- Vided forcrucible 7. The electrode 10 is brought near crucible 7 by means of theortion of the reaction chamber is filled with carbon, graphite, or othersuitable material as commonly used in the art, to the support 6; and theoperation of the furnace is started by lowermg'electrode 8 until itestablishes connection with the cover 13 of crucible 7. When used as aresister furnace, electrodes 8 and 10 are connected in series.

- The above description and drawings are not to be interpreted as in anyway limiting the seoege of this invention, \being merely intendembodiments thereof.

What] claim is :1,

1. In an electric furnace, a bod formed with a cavity having theshape 0two opposed paraboloids, means in said cavity for mamtainin a substancetobe heated-in the principal of said paraboloids, said means adaptedtoserve as a centef electrode for' two arcsin series.

2'.- In an electric furnace, a body having outer and -inner spaced wallsof refractory I material and having the space between said walls filledwith heat insulating material; said body formed interiorl of said innerwall with a cavity-having t e shape of two opposed paraboloids.

3. In an electric furnace, outer and inner s aced walls and heatinsulating terial in t e space between said walls; said furnace toillustrate one of many possible formed interiorly of said inner wallwith a reaction chamber having the shape of two opposed paraboloids; andmeans whereby said furnace may be used as an arc furnace and as aresistor furnace interchangeably.

4. In an electric furnace, outer and inner spaced walls and heatinsulating material in the space between said walls; said furnace formedinteriorly of said inner wall with a reaction chamber having the shapeof two opposed paraboloids; and a crucible coinposed of conductingmaterial in the principal foci of said paraboloids, said crucibleconstituting a center electrode for two arcs in series.

5. In an electric furnace, outer and inner spaced walls and heatinsulatin material in the space between said walls; and furnace formedinteriorly of said inner wall with a reaction chamber having the sha eof two opposed paraboloids; and a cruci le in the principal foci of saidparaboloids, said crucible constitutin a common electrode for two arcsin are el.

6. Inan e ectric furnace, outer and inner spaced walls of refractorymaterial, heat in- Sula-ting material in the space between said walls;said furnace formed interiorly of said inner wall with a reactionchamber in the form of two opposed paraboloids; a crucible in theprincipal foci of said paraboloids, said crucible adapted to cooperatewith means constitutin an arc heatin device; a second crucible alfaptedto be su stituted for the first mentioned crucible, said secondmentioned crucible further adapted to cooperate with means constitutinga resistance heating device. I

7. In an electric furnace, outer and inner spaced walls and heatinsulating material in the space between said walls; an arc heatingmeans in said furnaceand a resistance heating means adapted to besubstituted for said are heating means.

8. In an electric furnace, a body having outer and inner space betweenand walls filled with heat insulatin material; said bod -f'ormedinteriorly 0 said inner wall wit a cavity, and cavi having the shape oftwo opposed pa loids. 9. In an electric furnace, at bod :formed with acavity having the shape 0 t'wolopposed paraboloids, and means insaid-cavity or maintaining a substance to be in the principal oci ofsaid parabololds, said means adapted to serve as a common electrode fortwo arcs in parallel.

10. In an electric furnace, a body havmg outer and inner aced walls andhaving the space between said walls'filled heat-insulatingmatefi'al;said body formed orly of said inner wall with a cavity, and a cruciblein said cavity, said crucible consti tutin a common electrode for twoarcsin paral el. V

11. In an electric furnace, at body having 5 outer and inner spacedwalls and having the space between sud walls filled with heatins'ulating material; said body formed interiorly of said inner wallwith a, cavity, and a crucible in said cavity, said crucibleconstituting a common electrode for two arcs in 10 series.

In testimony whereof I ailix my signature.

CLAUDE G. MINER.

00p!" of this patent may be obtained for he cent! each, by addressingthe "commissioner of latentl, Washington, D. G.

